Paronychia brasiliana is a prostrate, tap-rooted, perennial, ruderal species of herb native to southern Brazil, Uruguay, N.E. Argentina. It is a troublesome weed in lawns and pastures, chiefly in poorly maintained ground with sandy soils. It can also be found around the margins of muddy pools that dry out in summer. In New Zealand, it is found in coastal North Island but only one specimen has been reported growing in an open ruderal environment at Motueka, South Island. It piece of land is a parking area for motorhomes, so it was possibly introduced by them.

The plants have branched, prostrate stems which are scabrous to finely hairy and they are often knotted and rather woody. The hairy, greenish brown leaves are linear to elliptic or obovate (narrower end at the base) 3–8 mm long, 1–2 mm wide, hairy and awned. P. brasiliana has very small green, flower-like structures that have no petals but have five stamens, 5 oblong sepals which are 1–2 mm long and are glabrous, reddish and end in awns 0.5–1 mm long. A single-seeded fruit is produced.